In a conventional type of data transmission from various types of media to other devices through a single transmission line, because transmission unit time periods of pieces of transmission data are the same as each other and data sizes of the pieces of transmission data are the same as each other, there is no problem. However, in a WCDMA data transmission, it is required to transmit pieces of data having transmission unit time periods and data sizes different from each other from various types of media.
FIG. 1 shows a data transmission between a wire transmission line interface unit 2 of a base band signal processing unit 1 of a radio base station device and a wire transmission line interface unit 4 of a radio network control device 3. Pieces of data are transmitted from the base band signal processing unit 1 to the wire transmission line interface unit 4 of the radio network control device 3 through the wire transmission line interface unit 2 and a transmission line 5 in the order in which the pieces of data are received in the base band signal processing unit 1.
FIG. 2 is a view explaining the conventional data transmission order by using both data A and data B. When a piece of data A having a long minimum processing time period TTI1 is transmitted, the transmission line 5 is occupied by the data A. Therefore, another piece of data B cannot be transmitted during the transmission of the data A. Accordingly, in cases where another piece of data B having a short minimum processing time period TTI2 is received, a momentary stoppage of the data transmission occurs, or the delay in the data transmission occurs in the device.
FIG. 3 shows a relationship between a transmission side and a reception side in the conventional data transmission. In cases where data A0 of the data A is transmitted after the transmission of data B3 of the data B, it is impossible to transmit data B4 of the data B until the transmission of the data A0 is completed. Therefore, as shown in FIG. 3, a momentary stoppage of the data transmission occurs between the data B3 and the data B4 on the reception side.
As is described above, pieces of data are transmitted in a conventional data transmission method and a conventional data transmission device in the order in which the pieces of data are made possible to be transmitted. Therefore, when data having a long processing unit time period is transmitted, the transmission line is occupied by the data for a long time period during the transmission of the data, and another piece of data cannot be transmitted during the transmission of the data. Also, even though the data having the long processing unit time period is divided into pieces of divided data and is transmitted, in cases where the pieces of divided data are successively transmitted, a transmission and occupation time period of the data is lengthened. Therefore, a momentary stoppage of the data transmission occurs, or the successive transmission of the pieces of divided data adversely influences on data having a short processing unit time period such as speech data in which a real time reproduction is seriously considered. Accordingly, a problem has arisen that a data arrival time fluctuates.
The present invention is provided to solve the above-described problem, and the object of the present invention is to provide a data transmission method and a data transmission device in which a data transmission is efficiently performed through a transmission line and the fluctuation of a data arrival time is minimized.